Power transmission



Sept. 29, 1936. F, FAWCETT POWER TRANSMISSION Filed Oct. 3Q, 1933 4 Sheets-Sheet l m @M/M ATTORNE Y Sept. 29, 1936. F.T. FAwcET'r `2,055,895 A POWER TRANsMIssloN Filed oct. 30, 1935 4 sheets-sheet 2 /N VE TOR www 'ATToR/vfy Sept. 29, 1936. F T, FAWCTT 2,055,895

POWER TRANSMISSION //V VEN TO/P ATTORNEY Sept 29, 1936- F. T. FAwcETT POWER TRANSMISSION Filed Oct. 50, 1935 4 Sheets-Sheefl 4 Patented Sept'. 29, 1936 PATENT oFFicE POWER TRANSmSSION Francis Thomas Fawcett, Woodford Green,

and

Application October 30, 1933, Serial No. 695,898 In Great Britain November 9, 1932 This invention relates to an automatically variable speed gear employing a hydraulic clutch of the Fttinger or like type and it has for its object to provide an improved speed gear wherein the transmission ratio is automatically made suitable forthe conditions of operation encountered;

An automatically variable speed gear according to the'invention utilizes a hydraulic clutch of the Fttinger or like type, having a driving element to which a power input is applied and a plurality of driven elements through which fluid is impelled successively from one to the other and this clutch is combined with gears so arranged that each driven element is connected to the output shaft with a different ratio, the

drive being taken u p successively by the different driven elements of the hydraulic clutch.

'I'he hydraulic clutch employed preferably utilizes an enclosing casing in which the driven elements are rotatably arranged, passages being formed in said casing andl in said elements.

through which the oil or other operating lfluid circulates. 'I'he circulation of the fluid is thus effected through the different driven elements successively and rotationall torque is applied by such fluid to said elements. When the output shaft is stationary, most torque is applied to the first driven element (i. e. that nearest the driving element) of the clutch since this element is stationary and after traversing the said first element the major part of the kinetic energy of the fluid Will be 10st,

Assuming, however, that'the output shaft is being accelerated, said first element is speeded up until its speed approximates that of the driving element whereupon the kinetic energy of the iiuid reaching the succeeding driven elementis increased so that the drive is gradually taken up through said second driven element when the first driven element attains the same speed as the driving element. In the same way the third element takes4 over the drivel when the second element has been accelerated, and so on. The drive is thus taken up successively through the different driven elements of the clutch until the driving torque is applied to the element most remote from the driving element, and which is conveniently connected to the output shaft 'di-fftinue to run at the same speed as the driving element while the following element or elements is/are being accelerated, free-wheel or one-way clutch mechanism is provided in conjunction with part at least of the gears connecting. Said driven elements to the output shaft. y

The driven element nearest the driving element is connected to the output shaft by gears having the-highest ratio while the succeeding concentric hollow shafts or sleeves are prefer- 15 ably adopted and associated driving gear wheels can be formed on or attached to the outer ends of said shafts o r sleeves. The final element may be xed to a solid shaft arranged. within the concentric sleeves and if desired the shaft mayv 2o be formed with a passage and openings for distributing lubricating oil.

The whole transmission means if required may be mounted in an outer casing comprising a l sump for assisting in the circulation of the oil. 25

y Although transmission means according to the invention can be used for a great variety ofvpurposes, they are'particularly advantageous for use -for motor road vehicles, locomotives and other similar uses.

In one particular transmission means accord ing to the invention for motor road'vehicles, the fluid clutch has three driven members and one driving member, which also serves as the fiywheel of the engine. .'lhethree driven members 35 are coupled to a first, second and top gear respectively, the first speed clutch member coming nearest to the engine driving portion, the second being placed next and so on, the top gear being the last. Consequently, as the engine is acceler- 40 ated the rotating iiuid from the' member of the fluid clutch connected to the engine will rst act upon the first gear member luntil this member reaches aspeed approaching the engine revolutiOllS- j 4s During this period the'second gear portion of the fluid clutch rotates more slowly than the first gear portion by a definite ratio depending on the sizes of the gear wheels. However, after the first gear portion has been accelerated to 50 engine speed, this portion continues to run at engine speed while the second gear portion of the fluid clutch takes up the drive, free-wheel mechanism permitting the first gear portion to run at engine speed and not at that definite 55 ratio to the second gear-portion to which reference was made above. Upon the second gear portion reaching the engine speed, the same process is repeated for the varioussuccessive positions and so on until direct drive is the result.

It should be particularly observed that the change from one gear speed to another is gradual and automatic, that is to say at certain points during the acceleration of the engine, the power will be passing through more than one gear at the same time until direct drive is obtained, thus eliminating all shocks and lost time.

Upon deceleration, such as when climbing a hill, the reverse process takes place, i. e. when a greater resistance is encountered, due to the ineline of the hill, slipping commences to taire place on the top gear fluid clutch. The drive then commences to be taken through the next lowest gear portion of the fluid clutch, since a smaller amount of engine torque will serve to drive the vehicle through this gear portion. If necessary the succeeding lower gear portions of the fluid clutch are engaged according to the requirements of the vehicle.

It should be n'oted that with transmission means according to the invention when the load is small, the gear is automatically maintained in the lowest ratio but directly the load is increased or the throttle opened, the gear ratio is immediately and automatically increased, thereby giving improved acceleration, for example in the case of a car, when passing slower vehicles and after rounding sharp bends or recovering from traillc blocks. the driver permitting the engine to labour at -too slow speed nor any possibility of excessive racing of the engine on low gears.

-In order that the invention may be more fully understood, the same will now be described by Way of illustration and not limitation with ref-t Fig. 4 is an enlarged sectional view of one forml of the invention wherein the mechanism is mounted in a casing and is applicable particularly for an automobile transmission.

Fig. 5 illustrates in section a modification wherein the parts of the clutch are of graduated size.

Fig. 6 is a cross sectional view of the mechanism on the line 6 6 of Fig. 1. f

In Fig. 1, 6 is the end of the engine shaft which carries the casing and driving member 1 o f the uid clutch. 'Ihe final driven member 8 of the fluid clutch is mounted upon 'a shaft 9 spigoted into the end of the driving shaft 8 and having a passageway therethrough for lubricating oil, said passageway terminating in distributing passages.

It will be observed that the final driven member 8 of the fluid clutch is located in the housing' thereof and in addition three intermediate driven members are mounted between the drivingportion 1 and the driven portion 8. 'I'hese driven members I0, II and I2 are carried by sleeves I3,

somewhat helical movement of the liquid abouta theoretical circumference when memberY 1 ro- Further, there is no possibility of tates relatively to the driven members I I, I 2 or 8.

'I'here is thus formed around the periphery of the fluid clutch, a series of annular passages through which the fluid (i. e. liquid) is projected by the rotation of driving element 1. Radially extendingI vanes (not shown in section) extend across said passages and serve to apply the desired motion to the liquid under the action of the centrifugal force produced on rotation of the driving element 1.

The free end of the sleeves I3 carries a gear Wheel I1 meshing with a gear wheel I8 carried by a lay shaft I9 with the interposition of the freewheel mechanism 20 of any known type. Said free wheel mechanism includes a pair of relatively movable plate members 2i]a and Zlib arranged on a threaded part of shaft I9. The former plate is rigidly fixed to said threaded part by means of grub screws for example, while the plate 20b is adapted to rotate on said threaded part and thereby be subjected to movement to the left or right according to the direction of rotation. The peripheral surfaces of the members 2da and 2lib are coned as indicated to engage correspondingly coned surfaces on the inner surface of an externally toothed ring constituting the gear wheel I8. It will readily be seen that anti-clockwise rotation of Wheel I8, when viewing Fig. 1 from the left toward the right, will cause plate member 2|]b to screw on the thread so as to move towards the plate member 20H and thereby form a driving connection between i8 and the supporting shaft. The spring pressed cup lillc in the plate member 20h normally urges the plate members 2li8L and 2l)b toward one another, so that the desired driving connection between the wheel I8 and the shaft 20 is effected instantaneously. When, however, gear wheel 2i tends to take over the drive, the supporting shaft tends to over-run wheel I8 land plate 20b moves to the right to free the wheel I8 and allow the supporting shaft to run faster than wheel I8.

Similarly, the sleeve I4 carries a gear wheel 49 of larger pitch diameter than the wheel I1 meshing with a gear wheel 2| mounted on the lay shaft I8 with the interposition of a freewheel mechanism 22 similar to 20, already described, the pitch diameter of the wheel 2| being smaller than that of the gear I 8.

The sleeve I5 also carries the gear wheel 23 larger than the gear wheel 49 and meshing with a gear 24 smaller than the gear 2| andxed to lay shaft I8.

The connection of the gear 24 to the lay shaft i9 does not include a freewheel mechanism but to the lay shaft is vxed a final gear wheel 25 meshing with a gear wheel 28 larger than the gear wheel 28 and carried by the end of the shaft 8 through a freewheel mechanism 21.

spigoted into the end of the shaft 9 is the driven shaft 28 which has slidably mounted thereon in such a manner that it is caused to turn therewith. one-half of a dog clutch member 28, the co-operating portion of which is carried by the shaft 8. 'I'he clutch member 29 also has a gear wheel 38 integral therewith and is adapted to be moved on the shaft 28 through suitable striking gear.

The lower part of the i'lgure has diagrammatically represented thereon a reversing gear comprising a toothed wheel 32 on a shaft 33 and permanently in mesh with layshaft gear 25. Shaft 33 also carries another toothed wheel 34. This representation of the reversing mechanism is shown angularly displaced from its normal ,when it commences to rotate a certain portion of the torquels applied to the other clutch members It should be understood that the clutch 2l' can be disengaged as shown on the drawings,

constituting a standstill or neutral position, or

can be engaged with the cooperating part, in which case the shaft 28 turns with the shaftv 9, or can be disengaged and slid so that 'the gear wheel 30 -meshes with the gear wheel 3i, thus causing the reverse drive to the shaft 28.

Another somewhat similar form of transmission means to that shown in Fig. 1 is shown in- Fig. 2. In this figure, the only substantial difference is that two intermediate stages I0l andv II only are shown and in addition the driving member 'I of the fluid clutch has turning therewith disc-like vaned members forspeeding up the liquid between the stages. The said vaned members, being connected to the clutch casing, are positively driven by the engine to obtain lthe required speeding up action. Also in this figure the ordinary toothed gears are replaced by doublehelical gears.

Againin Fig. 3, the construction is somewhat similar to that shown in Figs. 1 and 2, but in this casethree intermediate stages Iii, II and I2 are shown and speeding-up members 36 extending only about half the radial distance of the vanes are utilized and turn with the driving member 1. The freewheel devices are varied and as shown are comprised by one-way spring clutches 31 andin place'of the gears being located on a separate lay shaft, an Lepicyclic arrangement is adopted, a dog'clutch member 38 being adapted to be set in the neutral position as shown or in a forward or reverse position 39 or 40 respectively. In] this figure, di is a tlxed annulus and 42 a bracket supporting a fixed sun pinion 4 3. The rest of the construction will be obvious as it is simply a modification of the transmission means already described, the modifications being necessitated by arrangement.

Fig. 4 shows a somewhat similar'form ci the invention to that shown in Fig. l, but. with only two intermediate stages ill and II.

The driving member .l has associated therewith' the sprocket M for a self=starter and the bearings for the various shafts are mounted in a casing or sump 45. This casing also has associated therewith a three-position striking gear t6 controlled' by the usual lever il enabling the parts to be 'put in the neutral, forwarder reverse position. The

neutral position is shown in the drawings andthe' forward is given by the engagement of the dogclutch parts 2g, the vreverse being eected, by au additional shaft not shown but similar to 33 (Fig. 1), having suitable gears thereon, throughthecooperatiorl of the gear wheel 30. En addition a Cardan joint do is shown associated with the shaft 28. The free wheel mechanisms 22 and 2l also will be observed.

The method or operation will be particularly described with reference to Fig. 4 hereinafter, but

' it will be understood that the mechanism described with reference to the other iigures operates in a similarmanner. Assuming in the first place that the output shaft is stationary while the input or engine shaft is positively driven by the engine, this drives the clutch member 1. causing circulation of liquid around the annular space at the clutch periphery. The circulating liquid applies torque to clutch member it while the latter is stationary but the epicyclic II and I. If now the engine is accelerated, sumcient torque may be applied to clutch member I0 to cause rotation of the output shaft against the v load, it being understood that this member III is ydrive if the load is not too great. Member II is therefore gradually accelerated up to engine speed and during this period member I0 continues to rotate at thesame speed by virtue of the freeV wheel 22 incorporated in the, layshaft gear driven by said members. After member II has reached engine speed. the drive is taken up by member 8 and direct drive is obtained between engine shaft and output shaft. members I0 and I I rotating together at the same speed, since the free wheels 22 and 2l permit this to take place. Change of transmission ratio from one speed to another is thus obtained automatically according to requirements. The operation'is probably somewhat more complicated than that described above since when the speed of clutch member IIJ, is still somewhat less than 1 it is probable 'that some proportion of the torque is transmitted through member II.

ensuring a gradual transformation from one ratio to the next when the speed of I0 is equalized with that of 1.

The mechanism shown in Fig. 4 has operated satisfactorily in practice, being built to the dimensions of and replacing the normal clutch and gear rbox of a mass produced car.

Fluid clutches as utilized in transmission means according tothe present invention preferably are formed with filling openings whereby they can be readily charged, and if desired the fluid such as oil operating the said clutches can be included in and replenished by any suitable lubricating system. v

As shown in Fig. 5, the active diameters ofthe I driven elements of the clutch, It, Il and t, may be of progressively graduated diameter, that It) nearest the driving element l and connected to the Aoutput shaft by gearing having the greatest ratio,

having the greatest diameter.

Although in most forms it is preferred to enclose all the'stages of a fluid clutch according to the invention in one housing so that the whole forms a multi-stageiiuid clutch, yet `in certain cases,especiallyfor large installations, more than one separate fluid clutch may beutilized, the said separate fluid clutches constituting the various stages `-vand/or themselves each having intermediate stages and being connected to the load in an analogous manner to that already set forth.

The invention is not limited to the precise forms or details of construction described, as these may be varied to suit particular cases.

What I claim and desire to secure by Letters Patent of the United States of America isz- 1. An automatically variable speed gear connecting driving and driven shafts comprising a fluid clutch having a.y driving element connected to the driving shaft-and a plurality of driven elements, fluid passages being formed in said driving and driven elements common to all of said elements, concentric sleeves connected to some of said driven elements, gear wheels on the ends of said concentric sleeves remote from said' driven elements, a rotatable lay shaft, toothed members on said lay shaft meshing with the gear wheels on said concentric sleeves, a spindle passing through said concentric sleeves and connected to another driven clutch element, a gear wheel on said spindle, free-wheel mechanism between said gear wheel and said spindle, a toothed member on said lay shaft meshing with said last mentioned gear wheel, a further gear wheel slidably mounted on the driven shaft, striking means for sliding said further gear wheel, a reverse gear train between a further gearing element on said lay shaft and said further gear wheel and engageable by the latter in one position thereof, and means whereby said further gear wheel in its other extreme position connects said spindle to said driven shaft.

2. An automatically variable speed gear connecting driving and driven shafts comprising a uid clutch having a driving element connected to the driving shaft and a plurality of rotatable driven elements, annular passages being formed in said driving and driven elements around the periphery thereof, a sleeve connected to the driven element nearest the driving element, a gear wheel on the remote end of said sleeve, another sleeve concentric with the first sleeve connected to the second driven element, a second gear wheel of larger diameter than the first gear wheel on the remote end of said second sleeve, a spindle connected to the driven element furthest from said driving element, a third gear wheel on the remote end of said spindle, freewheel mechanism between the peripheral toothed part of said gear wheel and the part thereof connected to said spindle, a dog clutch element formed on the end of said spindle, said spindle being axially aligned with the driven shaft, a gear wheel slidably mounted on the end of the driven shaft, striking mechanism for moving said gear wheel into such position that it forms a driving connection between said spindle and said driven shaft, a rotatable lay shaft, three toothed members on -said lay shaft adapted to mesh with the gear wheels on said sleeves and on said spindie, free-wheel mechanism between the toothed periphery of one of said lay shaft gears and the lay shaft, a further gear Wheel on said lay shaft, and a reverse gear train meshing with said further gear wheel, one wheel of said reverse train being adapted to be engaged by the slidable gear wheel on the driven shaft when said gear wheel is moved into such position that it does not connect the said spindle and the driven shaft.

3. An automatically variable speed gear connecting driving and driven shafts comprising a fluid clutch forming a flywheel and embodying a driving element and a plurality of driven elements, annular passages being formed in said driving and driven elements around the periphery of said clutch, through which passages the liquid is successively projected by the centrifugal force set up in said passages and thereby turning moment is applied to the plurality of driven elements forming part of the said'clutch, conF centric means connecting said driven elements to a plurality of gear wheels of different sizes, a lay shaft, gears on said lay shaft meshing with the gears connected to the driven elements of the clutch, connecting means between said lay shaft and the driven shaft, means whereby said driven clutch members may be moved freely in one direction relatively to the others., and means connecting one of said driven elements to the driven shaft.

4. An automatically variable speed gear connecting driving and driven shafts comprising a ,fluid-clutch embodying a rotatable housing containing a plurality of driven clutch elements, annular passages being formed partly in said driven elements and partly in said housing whereby liquid contained in said housing is projected through the parts of the passages in the driven elements to apply turning movement to the latter, concentric means connecting said driven elements to a plurality of gear wheels of different sizes, a lay shaft having gears thereon adapted to mesh with the aforesaid gear wheels, connecting means between said layshaft and the driven shaft, means whereby each of said driven elements can rotate relatively to the others in one direction and means connecting one of said driven elements directly to the driven shaft.

5. An automatically variable speed gear as claimed in claim 4, wherein said clutch casing embodies means for accelerating the flow of liquid through said annular passage, said means comprising inwardly extending disc-like members located between the adjacent clutch elements and serving to accelerate the duid in said annular passages.

6. An automatically variable speed gear as claimed in claim 4, wherein radial vanes are provided in said annular passages.

'7. An automatically variable speed gear connecting driving and driven shafts comprising a uid clutch having a first terminal element provided with a curved liquid passage, a plurality of disc-like elements arranged face to face andv adjacent'said terminal element, said intermediate elements being provided with straight liquid passages, and a second terminal element provided with curved liquid passages corresponding in position to the liquid passages in the intermediate elements, toothed gears having a different ratio between the various intermediate elements and the driven shaft, means connecting the second terminal element directly to the driven shaft, and free-wheel mechanism permitting said intermediate elements or said second terminal element to turn freely in one direction relatively to the others.

S. An automatically variable speed gear connecting driving and driven shafts comprising a hydraulic clutch embodying a casing provided with a series of curved passages, a plurality of disc-like intermediate elements arranged one after the other adjacent the curved passages, a terminal element provided with a curved passage opening adjacent the passages in the disc-like .intermediate elements, toothed gears between the intermediate actuated elements and the driven shaft, the element nearest the curved passages in the casing having the highest ratio and the others having progressively lower ratios, a direct connection between the terminal actuated element most remote from the casing and the driven shaft, and means to permit any of said intermediate elements or said terminal element to rotate independently of the others in', one direction.

9. An automatically variable speed gear connecting driving and driven shafts, comprising a iiuid clutch having a first terminal element provided with curved liquid passages, a plurality of disc-like inrmediate elements arranged face to face and adjacent said terminal element, said intermediate elements being of progressively reduced diameters and being provided with straight liquid passages, a second terminal element provided withcurved liquid passagescorrespondin'g in position to the passages extending through said intermediate elements, gear wheels having a diierent ratio between the various intermediate elementsvand the driven shaft, means connecting lthe second terminal element directly to the driven shaft, and free-wheel mechanism permitting said intermediate elements or said second terminal element to turn freely in one direction relatively to the others;

10. An automatically variable speed gear connecting driving and driven shafts, comprisingfa iluid clutch having a rst terminal element pro- `vided with curved liquid passages-a plurality of disc-like intermediate elements arranged face to face and adjacent said terminal element, said- 20 intermediate elements having progressively reduced diameters, that of largest diameter being adjacent said terminal element and said intermediate elements being provided with straight liquid passages coincident vwith the passages in the said terminal element, a'second terminal element provided with curved liquid passages corresponding in position to the liquid passages in the intermediate elements, gear means connecting the intermediate elements to the driven shaft,

that element of largest diameter and positioned FRANCIS Timms r'awcrz'rr.l 

